The invention relates to peroxide vulcanizable polymeric compositions containing combinations of zinc dimethacrylate and various fillers or mixtures of fillers. More particularly, the invention relates to vulcanizable polymeric compositions containing natural rubber or copolymers of conjugated dienes and monoolefins, small amounts of a zinc dimethacrylate having specified surface area, various fillers or mixtures of fillers and peroxide curing agents. The invention further relates to certain vulcanizable polymeric compositions containing combinations of zinc dimethacrylate and clay which synergistically enhance the strength of the vulcanized compositions.
U.S. Pat. No. 3,823,122 relates to curable SBR or neoprene elastomer compositions containing from 1 to 15 parts by weight per 100 parts by weight of elastomer of a substituted acrylic acid or acid salt, with the preferred acid salt indicated to be zinc methacrylate. Elastomer compositions which are disclosed include a reinforcing filler such as carbon black but do not include a peroxide curing agent.
U.S. Pat. No. 4,082,288 discloses free-radical crosslinkable elastomer compositions containing a peroxide crosslinkable elastomer, from 10 to about 60 parts by weight per 100 parts by weight of elastomer of basic zinc methacrylate, a peroxide curing agent and optionally reinforcing fillers such as litharge or zinc oxide in amounts of 2 to 10 parts by weight per 100 parts by weight of elastomer.
U.S. Pat. No. 4,191,671 relates to curable rubber compositions comprising (A) a diene elastomer, (B) an alpha, beta ethylenically unsaturated carboxylic acid, wherein the ratio by weight of component (A) to component (B) is 87/13 to 55/45, (C) a divalent metal compound being present in quantities of 50 to 150 parts by weight per 100 parts by weight of component (B), and (D) an organic peroxide being present in quantities of 0.3 to 5.0 parts by weight per 100 parts by weight of the combined weight of components (A) and (B). The compositions may additionally contain an unpolymerizable carboxylic acid, carbon black in amounts of less than 50 parts by weight per 100 parts by weight of elastomer and an amine and/or phenol compound.
U.S. Pat. No. 4,192,790 relates to elastomer compositions having reduced Mooney viscosity in the compounded state. The Mooney viscosity of the elastomer compositions are reduced by the incorporation therein of from 0.1 to 7.0 parts by weight of basic zinc methacrylate per 100 parts by weight of elastomer. In addition to the basic zinc methacrylate, the elastomer compositions contain various elastomers or elastomer blends, an inorganic particulate filler such as silica, calcium carbonate, silicates such as clay, hydrated aluminum silicate and optionally carbon black (20 to 150 parts per 100 parts elastomer) and curing agents such as peroxide curatives.
U.S. Pat. No. 4,266,772 relates to solid golf balls formed from a curable elastomer composition comprising a free-radical crosslinkable elastomer, especially a peroxide crosslinkable elastomer, basic zinc methacrylate (about 10 to about 60 parts by weight per 100 parts by weight of elastomer) and a curing agent such as a peroxide curing agent. The compositions may optionally contain reinforcing fillers such as litharge or zinc oxide in amounts of for example 2 to 10 parts per 100 parts of elastomer.
British Pat. No. 1,091,818 discloses vulcanizable compositions comprising alpha-olefin polymers and a curing system consisting of metal salts of acrylic acid or methacrylic acid in amounts of from 1 to 10 parts of metal salt per 100 parts of polymer and an organic peroxide. The compositions may additionally contain reinforcing agents and fillers such as carbon blacks, metal oxides, clays and silica pigments.
British Pat. No. 2,042,553 discloses crosslinked cellular elastomeric compositions which are formed from an elastomer composition comprising a natural and/or synthetic rubber, a crosslinking agent such as a peroxide, a monomeric metallic salt such as zinc dimethacrylate, zinc diacrylate, preferably basic zinc methacrylate and a blowing agent. The compositions may additionally contain fillers such as carbon black or titanium dioxide and other known compounding additives.
While the aforementioned patents describe compositions which are similar in several respects to the compositions of the present invention, they fail to disclose or suggest two major elements of the present compositions. Thus, these patents fail to recognize the importance of using a zinc dimethacrylate having a surface area of from about 3.7 to about 5.4 m.sup.2 /g or more. Additionally, the patents neither disclose nor suggest compositions containing synergistic combinations of zinc dimethacrylate and clay.